1. Field of the Invention
The present invention relates to a video camera apparatus using a solid state image pickup device.
2. Description of the Related Art
By convention, a video camera apparatus has employed a solid state image pickup device as the combination of a CCD (charge coupled device) and optoelectric transducer elements. Remarkable progress of recent IC technology has increased the number of the picture elements (pixels) per unit area of the image pickup device. The increased number of pixels has greatly improved the picture quality of the image obtained by the video camera apparatus.
The increased number of the pixels, however, is attendant with many problems. Firstly, it needs a microfabrication technique. Because of this, the equipment to manufacture is increased and a production yield is degraded. Even if the image pickup device thus improved is used, in the case of the HDTV (high definition TV) system, the frequency band of the luminance signal is broader, i.e., 20 MHz or more. A great drive power for the horizontal transfer in the CCD is required. This results in increase of the size and weight of a power source section, e.g., a battery, and hinders a consistant tendency to the size reduction of the camera apparatus. Further, the larger the number of pixels per unit area is, the smaller the size of each pixel becomes. The quantities of charges for each pixel also become smaller. This leads to reduction of the sensitivity and S/N ratio. Additionally, if the image forming surface has a fine scratch, it appears in the reproduced image in the form of a relatively large drop of image. This fact contributes to degradation of the production yield.
One of the possible approaches to improve the sensitivity and the S/N ratio is to increase the device area with increase of the number of pixels per unit area. This approach, however, encounters a difficulty in manufacturing semiconductor devices of large area at a good production yield.
For the above reasons, under a condition that the device area remains unchanged, it is impossible to increase the number of pixels in the solid state image device. Further, there is a limit in increasing the device area. Additionally, the increase of the device area constitutes an unfavorable factor in reducing the camera size.